Method for stabilizing LiPF6, electrolyte solution for nonaqueous secondary batteries having excellent thermal stability, and nonaqueous secondary battery having excellent thermal stability
AssigneeTosoh F-Tech, Inc.
InventorsMasahiro Aoki, Hideyuki Mimura, Hisao Eguchi
Life of this patent
Estimating the term…
Abstract
A method for stabilizing a solution that contains LiPF6 by increasing thermal stability of LiPF6 without changing the structure thereof; an electrolyte solution for nonaqueous secondary batteries, which has increased thermal stability; and a nonaqueous secondary battery which has increased thermal stability. The solution containing LiPF6 contains a phosphoric acid ester amide in such an amount that the molar ratio of the phosphoric acid ester amide relative to LiPF6 is 0.001-2.
Claims11
A method for stabilizing LiPF6, comprising mixing a phosphoric acid ester amide represented by the following general formula (I) with LiPF6 in a solution comprising LiPF6, in such an amount that a molar ratio of the phosphoric acid ester amide with respect to LiPF6 is 0.001 to 2:
- where:
- m is 1 or 2;
- each of R1 and R2 represents a branched or linear alkyl group comprising 1 to 6 carbon atoms and/or a hydrocarbon group comprising an unsaturated bond, wherein R1 and R2 optionally comprise a substituent that is selected from the group consisting of an alkoxy group, an amino group, an alkylthio group, a saturated heterocyclic group, an unsaturated heterocyclic group, and a fluorine atom, and wherein R1 and R2 optionally combine together to form a 5 to 8 membered cyclic structure;
- and
- R3 represents a branched or linear alkyl group comprising 1 to 6 carbon atoms or a branched or linear fluorine-containing alkyl group comprising 1 to 6 carbon atoms.
A nonaqueous electrolyte solution comprising LiPF6 as an electrolyte and a cyclic carbonate and/or a chain carbonate as a solvent, and a phosphoric acid ester amide represented by the following general formula (I) in such an amount that a molar ratio of the phosphoric acid ester amide with respect to LiPF6 is 0.001 to 2:
- where:
- m is 1 or 2;
- each of R1 and R2 represents a branched or linear alkyl group comprising 1 to 6 carbon atoms and/or a hydrocarbon group comprising an unsaturated bond, wherein R1 and R2 optionally comprise a substituent that is selected from the group consisting of an alkoxy group, an amino group, an alkylthio group, a saturated heterocyclic group, an unsaturated heterocyclic group, and a fluorine atom, and wherein R1 and R2 optionally combine together to form a 5 to 8 membered cyclic structure;
- and
- R3 represents a branched or linear alkyl group comprising 1 to 6 carbon atoms or a branched or linear fluorine-containing alkyl group comprising 1 to 6 carbon atoms.
A nonaqueous secondary battery comprising a positive electrode and a negative electrode that are capable of occluding and releasing lithium, a separator, an electrolyte solution comprising LiPF6 as an electrolyte and a cyclic carbonate and/or a chain carbonate as a solvent and a phosphoric acid ester amide represented by the following general formula (I) in such an amount that a molar ratio of the phosphoric acid ester amide with respect to LiPF6 is 0.001 to 2:
- where:
- m is 1 or 2;
- each of R1 and R2 represents a branched or linear alkyl group comprising 1 to 6 carbon atoms and/or a hydrocarbon group comprising an unsaturated bond, wherein R1 and R2 optionally comprise a substituent that is selected from the group consisting of an alkoxy group, an amino group, an alkylthio group, a saturated heterocyclic group, an unsaturated heterocyclic group, and a fluorine atom, and wherein R1 and R2 optionally combine together to form a 5 to 8 membered cyclic structure;
- and
- R3 represents a branched or linear alkyl group comprising 1 to 6 carbon atoms or a branched or linear fluorine-containing alkyl group comprising 1 to 6 carbon atoms.
Dependencies are inferred from the claim text.